// ========================================================================
// Copyright (c) 2004-2009 Mort Bay Consulting Pty. Ltd.
// ------------------------------------------------------------------------
// All rights reserved. This program and the accompanying materials
// are made available under the terms of the Eclipse Public License v1.0
// and Apache License v2.0 which accompanies this distribution.
// The Eclipse Public License is available at 
// http://www.eclipse.org/legal/epl-v10.html
// The Apache License v2.0 is available at
// http://www.opensource.org/licenses/apache2.0.php
// You may elect to redistribute this code under either of these licenses. 
// ========================================================================

package org.eclipse.jetty.http;

import org.eclipse.jetty.io.Buffer;
import org.eclipse.jetty.io.BufferCache;
import org.eclipse.jetty.io.ByteArrayBuffer;

/**
 * Cached HTTP Header values. This class caches the conversion of common HTTP Header values to and from {@link ByteArrayBuffer} instances. The resource "/org/eclipse/jetty/useragents" is checked for a list of common user agents, so that repeated creation of strings for these agents can be avoided.
 */
public class HttpHeaderValues extends BufferCache
{

	public final static String
		CLOSE = "close",
		CHUNKED = "chunked",
		GZIP = "gzip",
		IDENTITY = "identity",
		KEEP_ALIVE = "keep-alive",
		CONTINUE = "100-continue",
		PROCESSING = "102-processing",
		TE = "TE",
		BYTES = "bytes",
		NO_CACHE = "no-cache",
		UPGRADE = "Upgrade";

	public final static int
		CLOSE_ORDINAL = 1,
		CHUNKED_ORDINAL = 2,
		GZIP_ORDINAL = 3,
		IDENTITY_ORDINAL = 4,
		KEEP_ALIVE_ORDINAL = 5,
		CONTINUE_ORDINAL = 6,
		PROCESSING_ORDINAL = 7,
		TE_ORDINAL = 8,
		BYTES_ORDINAL = 9,
		NO_CACHE_ORDINAL = 10,
		UPGRADE_ORDINAL = 11;

	public final static HttpHeaderValues CACHE = new HttpHeaderValues();

	public final static Buffer
		CLOSE_BUFFER = CACHE.add(CLOSE, CLOSE_ORDINAL),
		CHUNKED_BUFFER = CACHE.add(CHUNKED, CHUNKED_ORDINAL),
		GZIP_BUFFER = CACHE.add(GZIP, GZIP_ORDINAL),
		IDENTITY_BUFFER = CACHE.add(IDENTITY, IDENTITY_ORDINAL),
		KEEP_ALIVE_BUFFER = CACHE.add(KEEP_ALIVE, KEEP_ALIVE_ORDINAL),
		CONTINUE_BUFFER = CACHE.add(CONTINUE, CONTINUE_ORDINAL),
		PROCESSING_BUFFER = CACHE.add(PROCESSING, PROCESSING_ORDINAL),
		TE_BUFFER = CACHE.add(TE, TE_ORDINAL),
		BYTES_BUFFER = CACHE.add(BYTES, BYTES_ORDINAL),
		NO_CACHE_BUFFER = CACHE.add(NO_CACHE, NO_CACHE_ORDINAL),
		UPGRADE_BUFFER = CACHE.add(UPGRADE, UPGRADE_ORDINAL);

	public static boolean hasKnownValues(int httpHeaderOrdinal)
	{
		switch (httpHeaderOrdinal)
		{
			case HttpHeaders.CONNECTION_ORDINAL:
			case HttpHeaders.TRANSFER_ENCODING_ORDINAL:
			case HttpHeaders.CONTENT_ENCODING_ORDINAL:
				return true;
		}
		return false;
	}
}
